1. Field of the Invention
The present invention relates to a device and process for use in encoding audio data, and in particular to a psychoacoustic mask generation process for MPEG audio encoding.
2. Description of the Related Art
The MPEG-1 audio standard, as described in the International Standards Organisation (ISO) document ISO/IEC 11172-3: Information technology—Coding of moving pictures and associated audio for digital storage media at up to about 1.5 Mbps (“the MPEG-1 standard”), defines processes for lossy compression of digital audio and video data. The MPEG-1 standard defines three alternative processes or “layers” for audio compression, providing progressively higher degrees of compression at the expense of increasing complexity. The second layer, referred to as MPEG-1-L2, provides an audio compression format widely used in consumer multimedia applications. As these applications progress from providing playback only to also providing recording, a need arises for consumer-grade and consumer-priced devices that can generate MPEG-1-L2 compliant audio data.
The reference implementation for an MPEG-1-L2 encoder described in the MPEG-1 standard is not suitable for real-time consumer applications, and requires considerable resources in terms of both memory and processing power. In particular, the psychoacoustic masking process used in the MPEG-1-L2 audio encoder referred to uses a number of successive and processing intensive power and energy data conversions that also incur a repeated loss in precision.
Accordingly, it is desired to address the above or at least provide a useful alternative.